Double chamber infusion bag and method of manufacture

ABSTRACT

The invention provides an improved infusion bag, for containing tea, coffee or the like. The bag (10) incorporates means for compression, such as string (12) which is attached to bag (10), for example at its base (14) by knot (16). The bag of the invention may be single chambered or double chambered, inter alia. The invention also provides a method of manufacturing the bag.

FIELD OF THE INVENTION

This invention relates to infusion bags and the like; more particularly,this invention concerns an improvement intended to overcome some of thedrawbacks presently associated with such bags.

BACKGROUND OF THE INVENTION

The infusion bags relevant to this invention are those of the type whichcontain a measured quantity of substance enclosed in a membrane. Suchbags are intended for infusion, for example in a hot liquid, and mayincorporate a handle to facilitate both the suspension of the bag in theinfusion liquid and the removal of the bag from the liquid. In someforms, the handle constitutes a short length of string stapled or gluedto the bag. The free end of the string may have a tag attached for easyhandling.

The bag itself may take any number of configurations. The most commonform of bag represents a simple envelope or pouch, with walls of a thinporous paper-type material sealed on all edges (the "single chamber"bag). Another form of bag comprises a short length of tube or similarmaterial. The free ends of the tube are fixed together so that the tubeforms a loop which may be folded to any desired configuration (the"double chamber" or "flow-through" bag). In yet another form, the bagmay be spherical or drop-shaped. It is to be understood that the presentinvention is applicable to all types of infusion bags, whatever theirprecise shape.

It is well recognised that infusion bags have gained immense popularityin recent years. In particular, infusion bags containing tea or herbsare in common use in many parts of the world and billions of such bagsare sold every year.

While an infusion bag has many advantages and is generally convenient touse, it does suffer from two major drawbacks. The first arises after thebag has been immersed in the infusion liquid for the required period oftime and it is desired to remove the bag from the liquid. It isinvariably the case that residual liquid drips from the bag as it iswithdrawn and care must be taken to ensure that the dripping liquid doesnot wet or stain surrounding surfaces or material.

The second drawback relates to the extraction of maximum flavour fromthe infusion bag. Simple infusion is not always sufficient for thispurpose. Where the infusion bag is provided with a handle, the bag maybe stirred through the infusion liquid by using the handle to oscillate(or "jiggle") the bag through the liquid and this can aid extraction.However, this method falls short of effecting maximum extraction.

Both drawbacks have been recognised and there have been attempts toovercome the drawbacks. For example, where the infusion bag is intendedto be used to produce a cup of tea, some users employ a teaspoon orsimilar implement to squash the teabag between the teaspoon and theinternal surface of the cup while this method can assist in extractingextra tea flavour from the bag, the method has very little success inpreventing drips unless the bag can be held clear of the infusing liquid(hot water) during the operation. Normally, there is a maximum of twocentimetres between the surface of the water in the cup and the lip ofthe cup. As a result, there is inadequate dry cup surface and thesquashing method is not very effective. There is also the substantialdanger that pressure on the inside surface of the cup, adjacent the lip,will cause the cup to tip and spill its contents.

In another prior art attempt to overcome the aforesaid drawbacks, a pairof tongs has been provided for squeezing infusion liquid and flavourfrom the bag. This method is somewhat more successful than the firstmethod described above. However, one of the main advantages of infusionbags is their convenience in terms of storage and transportation, aswell as their low manufacturing cost. It is not always convenient tohave access to a pair of tongs for use with infusion bags; the provisionof one of more pairs of tongs in cartons of infusion bags would addsubstantially to costs.

More sophisticated attempts to overcome these problems are disclosed inU.S. Pat. No. 2,878,927 (Haley), in U.S. Pat. No. 3,327,550(Christopher) and in U.S. Pat. No. 3,396,032 (McCrae et al). However,each of these attempts involves a combination of an external harness onthe infusion bag coupled with complicated means for tightening theharness and squeezing the bag.

It is an aim of the present invention to provide an improvement whichovercomes or substantially alleviates the drawbacks referred to aboveand which moreover is inexpensive to implement.

Accordingly, this invention provides an improved infusion bag having abase and an apex and incorporating means for compressing the bag,characterised in that the compression means are provided in the form ofa flexible handle at least a portion of which is located within the bag,the flexible handle being secured at or near the base and adapted topass slidably through a substantial portion of the bag so that saidhandle is capable of compressing said bag by drawing said apex towardssaid base.

The invention also provides a method of manufacturing an improvedinfusion bag, comprising the steps of forming a bag and incorporating inthe bag at least a portion of the compression means.

In a preferred embodiment of the infusion bag of the invention, theflexible handle is a string, forming a loop secured to the bag in atleast one location in addition to the base. In use, the free end of thestring (which may or may not have a tag attached) may be used to suspendthe bag in the infusing liquid until it is desired to remove the bagfrom the liquid. At that time, as the bag is lifted clear of theinfusing liquid by means of the string, the bag is compressed by slidingthe bag along the string towards the base of the bag.

This compression action removes a substantial portion of infusing liquidfrom the bag and may also have the effect of maximising extraction offlavour from the bag. It is found that once the compressive force on thebag is released, provided the bag is still above the surface of theinfusing liquid, there is insufficient infusing liquid remaining in thebag to cause dripping.

The compression means of the invention may be adapted to anyconfiguration of infusion bag and may comprise systems other than thatdescribed above. Some of those other systems are described below.

The flexible handle, which may be a string or the like, may consist of amulti-stranded string, with different strands being attached to variousparts of the bag. The purpose of this configuration may be to enhancecompression of the bag, or to facilitate manufacture, or both.

In another form of the invention, the string may form a loop which isthreaded through the bag or which is fixed to the bag in one or morelocations.

In yet another form of the invention, two or more strings may beprovided in order to enhance compression of the bag and/or to facilitatemanufacture. The manner of fixing the string to the bag (or each string,if more than one) includes any method which is effective and convenient,including the use of knots, staples, glue, threading and the like.Depending on the effect desired, the method of fixing the string to thebag may permit the string to slide through the bag, or else the stringmay be anchored to the bag at one or more sites so that the stringcannot slide through the bag at those sites. The choice of manner offixing the string to the bag in any given configuration will bedetermined by the objectives in each situation and the range of choiceswill be readily apparent to one skilled in the art.

If desired, the improved infusion bag according to the invention mayinclude means to facilitate compression of the bag. For example, wherethe handle is a short length of string it may be provided with a tag,button or similar device, slidably mounted on the string between the bagand the free end of the string, so that the device may be used to assistthe compression by the user's fingers and to prevent scalding by contactwith hot infusing liquid. In this embodiment, the tag may be releasablyfixed to the free end of the string so that the bag resembles aconventional bag, with the tag carrying the usual manufacturer's trademark, for example. However, when the bag is to be compressed, the tag isreleased from the end of the string and is able to slide towards the bagas already described. Where the string is multi-stranded or more thanone string is provided, it is preferred that the means for facilitatingcompression of the bag, if used, are slidably mounted on all strands ofthe string or on all strings.

If desired, the bag may be manufactured so that the means forfacilitating compression of the bag (such as a tag) are an integral partof the bag. For example, the tag may comprise a part of the bag asdescribed in Australian Patent No. 118,215 (Sailsberg), with the zonewhere the tag joins the bag being weakened by perforations or the like,so that the tag, with string attached, may be detached from theremainder of the bag before infusion.

The invention is applicable to both single and double chambered infusionbags, inter alia. In the case of double-chambered bags, in which eachchamber is attached to the other at the base and the apex, the stringforming the compression means may be fastened at the base of the bag, sothat the string passes between the two chambers through the apex. Inthis event, it may be desirable to fix the two chambers of the bagtogether (for example, by using glue or heat-sealing) at an additionalpoint between the base and the apex so that during compression the twochambers do not fall away from the string, making compression lesseffective.

It will be noted that the compression means is regarded as within theinfusion bag in accordance with the invention when the compression meanspasses between the two chambers.

BRIEF DESCRIPTION OF THE DRAWINGS

Certain embodiments of the infusion bag of the invention, as well as oneembodiment of a method of manufacturing the infusion bag of theinvention, are described below in connection with the Drawings, inwhich:

FIG. 1 is a front elevation of one form of an improved infusion bagaccording to the invention;

FIG. 2 is a perspective view of a second form of an improved infusionbag according to the invention; and

FIG. 3 is a front elevation of a third form of improved infusion bag inaccordance with the present invention;

FIG. 4 is a diagrammatic view of a fourth embodiment of infusion bag;

FIG. 5 is a diagrammatic view of a fifth embodiment;

FIG. 6 is a diagrammatic view of a sixth embodiment; and

FIG. 7 represents a diagrammatic view of a seventh embodiment of theinfusion bag of the invention; and

FIG. 8 represents a schematic view of an embodiment of the infusion bagof the invention, especially suitable for containing coffee.

In the Drawings, like parts carry the same numbers for ease ofreference.

Referring first to FIG. 1, bag 10 is of conventional envelope type("single chamber") and contains tealeaves or other infusable material(not shown). Suspension string 12 passes through bag 10 (as shown indotted outline) and is retained at a point on base 14 of bag 10 by aknot 16. String 12 also passes through apex 17 and tag 18 and is securedthereto by a weak staple or loop 20.

To compress bag 10, tag 18 is urged towards bag 10 until loop 20releases the tag, which is then able to travel down string 12 to apex17. Continued pressure on tag 18 towards base 14 while string 12 is heldtaut results in compression of bag 10 with the resultant expulsion ofliquid and flavour therefrom.

In FIG. 2, infusion bag 10 is of the folded tube type ("doublechamber"). Compression is effected in much the same fashion as in thecase of the embodiment described in FIG. 1, except that because the freeend of string 12 has no tag, compression is effected by the user slidinghis fingers along string 12 towards apex 17 of bag 10 and thencontinuing to compress bag 10 towards base 14. The two chambers undergoeffective compression because they are held together by heat sealing(not shown), located approximately midway between base 14 and apex 17.

The infusion bag in FIG. 3 is drop or tear-shaped. String 12 is securedinside bag 10 near base 14 by means of a staple or loop 22. Disc 24 onstring 12 can be employed to assist compression of bag 10 in the samemanner as tag 18 in FIG. 1.

Referring to FIG. 4, bag 10 is of conventional envelope type ("singlechamber") and contains tealeaves or other infusable material (notshown). Suspension string 12 is double-stranded and enters bag 10 ataperture 30, Thereafter, the two strands of string 12 are separated intostrand 12a and strand 12b which are fixed to bag 10 at points 32 and 34.The manner of fixing may be by threading the strands through bag 10,optionally knotting each strand and returning each strand into bag 10.Alternately, strands 12a and 12b may be stapled to the bag at points 32and 34. The use of knots will obviously prevent strands 12a and 12b fromsliding through the bag 10. On the other hand, the threading of thestrands through bag 10, without knotting, or the use of suitablestaples, will permit sliding of strands 12a and 12b.

The choice of the manner of fixing will determine the effect when bag 10is compressed.

In FIG. 5, string 12 forms a loop entering bag 10 at aperture 30 and isfixed to bag 10 at points 32, 34 and 36. The manner of fixing may be anyof those described in connection with FIG. 4.

In FIG. 6, the configuration is similar to that in FIG. 4, except thatthere are two strings 12c and 12d which enter bag 10 at aperture 30.String 12c is fixed to bag 10 at point 32, while string 12d is fixed tobag 10 at point 34. In this case, the manner of fixing does not permitstrings 12c and 12d to slide through bag 10, except via aperture 30.Strings 12c and 12d are linked together at 38 by knotting together orsimilar means.

Referring now to FIG. 7, string 12 forms a continuous loop, one part ofwhich enters bag 10 at aperture 30a and the other part at aperture 30b.String 12 is threaded through the sides of bag 10 as generally indicatedat 40 and 42 and is able to slide freely at the threading apertures.

In FIG. 8, bag 10 has a base 14 with cutaway corners 44 and 46. String12 is secured to base 14 by looped stitching 48, or by a staple (notshown).

As indicated, the present invention also provides a method ofmanufacturing the improved infusion bag. A preferred embodiment of thiswill now be described.

In the production of a conventional "flow-through" or "double-chambered"tea bag, a length of filter paper is formed into a continuous "U" havingupstanding arms. The filter paper has deposited upon it, in fixeddosages, two separate mounds of tea for each bag. The upstanding armsare then brought together, folded and sealed to form a long closed tubewhich is cut into smaller teabag tubes, each containing two mounds oftea.

Next, three cross-folds are made in the centre of each teabag tube sothat a "W" is formed. The free ends of the tube are then broughttogether, folded in a triangular fashion and sealed by an aluminiumstaple. At this stage, one end of a cotton thread or string may also befixed to the bag by the staple. If desired, the other end of the stringmay be fixed to a tag by a staple.

To manufacture a double-chambered infusion bag according to theinvention, the conventional method of production may be followed, up tothe stage of folding the free ends of the teabag tube in a triangularfashion. Instead of sealing the triangular folds with a staple, extrasteps are required.

A needle threaded with a loop of string is inserted through thetriangularly-folded top section. The needle travels towards the base ofthe bag, to the region of the centre cross-fold. A staple is applied tothe cross-fold to restrain the string and lock it to the base of the bagwhile the needle retracts above the bag. The insertion of the staple atthe base of the bag may take place at the same time as the insertion ofthe staple at the triangular apex of the bag. Thereafter, the infusionbag of the invention may be finished as with conventional bags: a tagmay be applied to the free end of the string by means of a staple.Alternately, the tag may be slidably affixed to the string as describedabove.

It will be apparent to one skilled to the art that other embodiments ofthe infusion bag of the invention may be manufactured in a similar ordifferent manner. The invention is not to be limited by the specificexamples referred to herein, but only by the attached claims.

I claim:
 1. An improved infusion bag comprising a double chamber, a base and an apex, each chamber being attached to the other at the base and apex, the bag incorporating means for compressing the bag, characterised in that the compression means are provided in the form of a flexible handle at least a portion of which is located within the bag, the flexible handle being secured at or near the base and adapted to pass slidably between said chambers, each chamber being additionally attached together in a region between the base and the apex, so that said handle is capable of compressing said bag by drawing said apex towards said base.
 2. An improved infusion bag as claimed in claim 1, which further includes means to facilitate compression of the bag.
 3. An improved infusion bag as claimed in claim 2, wherein the means for facilitating compression of the bag comprise one of a tag and button slidably mounted on the handle outside the bag.
 4. An improved infusion bag as claimed in claim 2, wherein the means for facilitating compression of the bag form an integral part of the bag during manufacture and are adapted to be separated from the bag for use.
 5. A method of manufacturing an improved infusion bag having a double chamber, a base and an apex, each chamber being attached to the other at the base and apex, the bag incorporating means for compressing the bag, characterized in that the compression means are provided in the form of a flexible handle at least a portion of which is located within the bag, the flexible handle being secured at or near the base and adapted to pass slidably between said chambers, each chamber being attached together between the base and the apex, so that said handle is capable of compressing said bag by drawing said apex towards said base, the method comprising the steps of forming the bag, having the double chamber, providing an additional point for attaching the chamber together in a region between the base and the apex, and incorporating in the bag at least a portion of the flexible handle.
 6. A method of manufacturing an improved infusion bag having a double chamber, a base and an apex, each chamber being attached to the other at the base and apex, the bag incorporating means for compressing the bag, characterized in that the compression means are provided in the form of a flexible handle at least a portion of which is located within the bag, the flexible handle being secured at or near the base and adapted to pass slidably between said chambers, each chamber being attached together in a region between the base and the apex, so that said handle is capable of compressing said bag by drawing said apex towards said base, the method comprising the steps of:forming a length of filter paper into a continuous "u" shape having a flat portion and upstanding arms; depositing on said flat portion in fixed dosages two separate mounds of infusion material for each infusion bag to be formed; folding and sealing said arms to form a tube; cutting said tube into smaller infusion bag tubes, each containing two mounds of infusion material and having opposite open ends; folding each smaller tube to form a "w" shaped cross-fold; folding said ends in triangular fashion and sealing said opposite ends together to form the double chamber; attaching the chambers together in a region between the apex and base of the bag; inserting through the triangular fold so formed a needle threaded with string; causing said needle and said string to travel to the center of said cross-fold; stapling said string to said center; and stapling said string to said triangular fold so that said string is slidable within the staple. 